Method of protecting timbers against marine borer attack



METHOD OF PROTECTING TIMBERS AGAINST MARINE BORER ATTACK Filed June 4,1958 O. E. LIDDELL April 3, 1962 3 Sheets-Sheet l -"1"" INVENTOR. 'v/520. 0/2/41. 5 4/005 BY f 7 fi :11; M

fltomee 6 April 3, 1962 Filed June 4, 1958 o. E. LIDDELL 3,027,610

METHOD OF PROTECTING TIMBERS AGAINST MARINE BORER ATTACK 3 Sheets-Sheet2 INVENTOR. 0mm E. 000511.

vizier/23,5

o. E. LIDDELL 3,027,610

METHOD OF PROTECTING TIMBERS AGAINST MARINE BORER ATTACK April 3, 1962 5Sheets-Sheet 3 Filed June 4, 1958 ufrl glill:52???" R. mM 5 m a a H T WI m r M a F? 1 T. i L E :E u w. T r a m; H WW 0 v T. \.i .1: Y E E E E B3,627,619 h IEIHSI) PRGTEQTING TIMBERS AGAINST li IARINE IlGRER ATTAEKGrval E. Liddell, R0. Box 142, Avalon, Calif. Fiied June 4, 1953, Ser.No. 739,771 4 Eiairns. (til. Ell-1W) The present invention relates to anovel method for the protection of submerged wooden structures againstmarine borer attack.

It is a major object of my invention to provide an improved means andmethod of protecting a submerged wooden structure against marine borerattack.

Another object of my invention is to provide a method for contracting aloosely fitted tubular encasement into engagement with a pile throughoutthe length of the encasement from the surface of the body of water inwhich the pile is located without the aid of any underwater workers.

Yet another object of the invention is to provide a method of applying aprotective encasement of this type within a limited working space, asbetween the deck of a pier and the water line, and by unskilled workersworking on the surface of the water without the use or" specializedequipment whereby installation can be accomplished without removal ofthe decking.

A further object of the invention is to provide a method of this typecapable of use on all lengths and diameters of piles and especially onolder but still usable piles such as have had large surface areas eatenaway by borers so that they no longer have a uniform taper or diameter.

It is also an object of the invention to provide an encasement for pilesthat can be fabricated from commercially available materials at a costlower than that of prior devices and having a simplified method ofinstallation whereby the expense of protecting new and old piles againstmarine borer attack is greatly reduced.

A more particular object of the present invention is to provide a methodof protecting a submerged wooden pile against marine borer attack bywrapping a sheet of pliable substantially waterproof material about saidpile until said sheet engages said pile throughout the pile section tobe protected. Thereafter, the sheet is secured about said pile to definea generally circumferentially water-filled space between the pile andthe sheet to thereby restrict circulation between said space and thewater surrounding said sheet. In this manner the water in said space ismaintained stagnant and marine borers are prevented from sustainingthemselves within this space.

These and other objects and advantages of my invention will be apparentfrom the following description thereof when taken in conjunction withthe annexed drawings in which:

FIGURE 1 is a plan view of a first form of encasement embodying myinvention;

FIGURE 2 is a partial sectional view, on an enlarged scale, taken alongthe line 2-2 of FIGURE 1 and showing a first form of pole piececonstruction;

FIGURE 2a is a view similar to FIGURE 2 showing another type of polepiece construction;

FIGURE 3 is a perspective view showing a method of installation of theencasement illustrated in FIGURE 1;

FIGURE 4 is a horizontal sectional view showing an encasement looselyarranged in tubular configuration around a pile and indicating themethod of contracting the encasement into snug engagement with the pile;

FIGURE 5 is a View similar to FIGURE 4 but showing the encasement infully contracted condition;

FIGURE 6 is a partial sectional View of the area 6 of FIGURE 5, on anenlarged scale, particularly showing 3,027,619 Patented Apr. 3, 1962.

ice

the method of maintaining the encasement in snugly fitting engagementwith the pile;

FIGURE 7 is a partial sectional view, on an enlarged scale, taken alongthe line 77 of FIGURE 1 and showing a first form of socket means forholding a pair of pole pieces together;

FIGURE 7a is a view similar to FIGURE 7 showing another form of socketconstruction;

FIGURE 8 is an elevational view of an encasement in place on a pile witha skirt portion at the lower end thereof held closed against the pile bya novel form of skirt closing means;

FIGURE 9 is a perspective view showing the form of skirt closing meansutilized in FIGURE 8;;

FIGURE 9a is a partial perspective view, on an enlarged scale, showingcertain details of construction of a skirt closing means;

FIGURE 10 is a view similar to FIGURE 8 showing a form of protectiveboot applied over the lower end of the encasement and showing anotherform of band for closing the upper end of an encasement, another bootbeing illustrated in position for lowering into place above the upperend of the encasement;

FIGURE 11 is a partial elevational view, on an enlarged scale, showingthe upper end boot of the encasement in place;

FIGURE 11a is a view similar to FIGURE 11 showing an alternate form ofupper end boot;

FIGURE 12 is a horizontal sectional view, on an enlarged scale, takenalong the line 12-12 of FIGURE 10;

FIGURE 13 is a perspective view of an alternate form of closing bandparticularly adapted for use at the upper end of an encasement;

FIGURE 14 is a plan view of a part of another species of encasement ofmy invention;

FIGURE 15 is a partial sectional view, on an enlarged scale, taken alongthe line 15-15 of FIGURE 14;

FIGURES 16 through 20 are elevational views illustrating successivesteps in applying the encasement sheet of FIGURE 14 to a pile;

FIGURE 21 is a horizontal sectional view, on an enlarged scale, takenalong the line 21-21 of FIGURE 18 illustrating the manner of contractingthe encasement into intimate engagement with the pile; and V FIGURE 22is a detail sectional view, on a further 'enlarged scale, of the area 22of FIGURE 21.

In the drawings, I have illustrated my improved encasement as beingparticularly adapted for application to piles. that the principles ofconstruction herein disclosed are not necessarily so limited and can beutilized with certain other types of submerged structures.

In general the encasement comprises a substantially rectangular sheet ofa pliable material preferably tailored to conform to the dimensions ofthe pile to which it is to be applied, including any taper that may bepresent on, the pile. This sheet is rigidly reinforced against bendingalong at least a portion of the opposite vertical edges of the sheet.The rigidity of the reinforced edges enables the entire unit to bemanipulated from the surface of the water, as from a small skiff, toarrange the encasement in tubular configuration around the pile.Thereafter, the pair of reinforced edges are brought together androtated in unison to contract the encasement into engagement with thepile. A fastening means on the pair of reinforced edges is thenconnected to the pile to hold the reinforced edges against counterrotation whereby the engagement of the encasement around the pile ismaintained.

The encasement sheet is preferably made of a waterproof material whichis also preferably elastic, but it is believed that neither of thesequalities is essential. I

However, it will appear to those skilled in the art prefer to use rubberor neoprene which have these qualities but may also use polyvinylchloride which has these qualities to a lesser degree, or may use awoven fabric which is practically inelastic and still less waterproof.The sheet should be substantially waterproof, however, in the sense thatwhile it may be porous the ratio of the volume of pores or intersticesto the volume of mass restricts the circulation of sea water around theencased timber to such an extent that the rate of circulation is lessthan that required to sustain marine borer life. When the salt, oxygenand organic matter which the borers extract from the sea to sustainthemselves are not supplied at a sufficiently high rate the borers dieas a consequence. the extent to which the rate of circulation must berestricted will vary according to the type of borer, the salt, oxygenand organic matter content of the sea and other local conditions and istherefore subject to many variables.

In any event, the total rate of circulation into the encasement, throughthe material of the sheet or into the ends of the encasement, must below enough to arrest or prevent marine borer activity, i.e. create atoxic condition of stagnation inside the encasement wherein the wa terlacks supplies of salt, oxygen and organic matter in amounts sufiicientto sustain life.

In the drawings I have shown two specific species of encasement with twodifferent modes of application to piles. In each case, the encasement isshown with certain details of construction. However it is to beunderstood that such details of construction are not necessarilyconfined to the species of encasement with which they are shown and inmany instances can be applied to either of the illustrated species ofencasement.

Referring now to FIGURE 1, a first species of encasementisillustratedtherein and identified generally by the numeral 30. This encasementincludes a substantially rectangular thin sheet 32 of a pliablesubstantially waterproof material, preferably elastic in nature, cut toa length at least as great as the area of the pile to be protectedagainst marine borer attack. The sheet 32 throughout its length is of awidth preferably greater than the corresponding circumference of thepile and the opposite vertical edges 34 of the sheet are preferably cutwith a taper conforming to the taper of the pile. Where the area of thepile which is to be protected is relatively short, the taper of the pilecan be ignored. However in order to achieve aneat construction it isordinarily preferable to tailor the sheet with tapered opposite verticaledges.

Each of the edges 34 is rigidly reinforced against bending by a polepiece 36 whose detail construction is illustrated in FIGURE 2. Each ofthe pole pieces 36 includes a semi-cylindrical filler member 38 of wood,metal, plastic or the like over whose arcuate face one edge portion ofthe sheet 32 is placed. A semi-cylindrical member 40, preferably ofmetal and having a cavity adapted to receive both the edge portions ofthe sheet 32 and the filler member 38, is then placed around theseelements and the Whole held in assembled relationship by a plurality ofrivets 42 or other suitable fastening means. The metal parts can be madeof ordinary steel, galvanized metal, copper alloy or hearing metals suchas brass or Monel metal, and like materials such as are adapted toresist the corrosive effects of sea water.

Instead of the pole piece construction just described, in some cases itis preferable to employ a pair of pole pieces 36a of the type shown inFIGURE 2a. This alternative comprises a semi-cylindrical wooden member,preferably creosoted to resist attack by marine borers. It is to beunderstood however that treatment with creosote or other artificialchemical agents is not essential since the wooden pole pieces 36a can beprotected against borers in the same way as a pile; i.e. by wrappingthem in portions of the sheet 32. I have also found that while manyspecies of wood are satisfactory for use as pole l pieces, a close,straight grain wood such as clear white pine or apitong mahogany ispreferred.

Referring now to FEGURE 1 it will be seen that both of the pole pieces36 extend upwardly above the upper edge of the sheet 32 but at the lowerends terminate above the lower edge of the sheet 32. In order to exposethe lower ends of the pole pieces 36 so that they can be coupled in amanner hereinafter set forth, the opposite vertical. edge as of thesheet 32 are cut out and relieved as indicated at 44. As is indicated inFlGURES 2 and 2a the pole pieces are preferably afiixed to the verticaledges of the sheet 34 with their flat sides on the same surface of thesheet. Thus, when the encasement 39 is placed in tubular configurationaround a pile the flat sides of the pole pieces face one another andtheir lower ends are exposed to one another without any barrier ofportions of the sheet 32.

Those portions of the pole pieces 36 which extend above the upper edgeof the sheet 32 provide a pair of handles 48 by means of which theencasement 36 can be manipulated for placement around a pile St) in themanner shown in FIGURE 3. Thus, a man standing in a skiff or the like onthe surface of the water can hold both pole pieces 36 in one hand bymeans of the hendles 48 while the other hand is passed around the pile.The other hand then takes one of the pole pieces 36 to draw the sheet 32around the pile Sii. It will particularly be observed that theencasement 30 for the major portion of its length can be submerged inthe body of water 52 during this operation and the encasement 30 willtherefore assume a buoyancy which makes it relatively easy for a singleman to manipulate even a very long encasement 3ft. It also frequentlyhappens that a number of piles will be closely spaced together so thatit would be quite diificult to apply a tubular casing thereto by firstaligning it above the pile and then lowering it around the pile. Withthe method of installation just described, as long as there issufiicient space between adjacent piles for a person to pass his handtherethrough, or to admit the thickness of one of the pole pieces 36 myimproved encasement can quite easily be placed around the pile. Thismethod of installation is also important in those instances where a deck(not shown) is supported on top of the piles in close proximity to theSurface of the body of water 52. Where the upper end of the piles areobstructed-whereby working space is limited in this fashion nodifficulty has been encountered in making successful installations ofencasements.

After the encasement 3% has been wrapped around the pile 50 in themanner shown in FIGURE 3 the lower ends of the two pole pieces 36 arereleasably joined by means provided on the lower ends of the two polepieces. The lower end of one of the pole pieces 36 is provided with asemi-cylindrical socket 525 having a cavity 54 adapted to loosely orslidably receive the exposed lower end of the wooden member 38 of theother pole piece 36, the socket 52 being held on its pole piece 36 byscrews 56 or other suitable fastening means' As is indicated in FIGURE3, by manipulation of the handles 48, the exposed lower end of thewooden member 38 of the one pole piece 36 can be inserted into thecavity 54 of the socket 52 on the other pole piece 36. Thereafter thetwo pole pieces 36 are brought together to define a substantiallycylindrical unit or assembly.

FIGURE 7a illustrates another type of socket 52a on one of the woodenpole pieces 36a. In this case a semicylindrical cavity 5% is defined bya portion of the sheet 32 such as would otherwise be a part of one ofthe cutout portions 44. Alternatively the socket 52a can be made of aseparate piece of elastic waterproof material vulcanized or otherwiseafiixed in position on the sheet 32. The socket 52a is utilized inprecisely the same manner as the socket 52.. To facilitate connection ofthe two pole pieces, the socket cavity can be enlarged and can also betapered.

.AA A .11

After the two pole pieces 36 have been brought together to define acomplete cylindrical enclosure around the pile 50, the encasement 30 ismoved to the desired vertical position on the pile. Thereafter the pairof pole pieces 36 are rotated in unison, as is indicated in FIGURE 4, tocontract the encasement 39 into engagement with the pile t} (FIGURE 5).The force of this engagement will be sufficient to hold the encasement30 against slipping downwardly on the pile 50. However, in order to aidin holding the encasement 36 in place, but primarily to hold the pair ofpole pieces 36 against counter-rotation in a direction such as wouldpermit loosening of the sheet 32, a lag bolt 60 is inserted throughaligned bores 62 in the handle portions 48 of the pole pieces andfastened directly to the pole 50.

I have found that the use of a socket at the lower end of the polepieces and a fastener, such as the lag bolt 6% at the upper end of thepole pieces is ordinarily sufiicient to hold the two pole piecestogether during contraction of the encasement. However, in someinstances it may be desirable to fasten the two pole pieces 36 or 364:together at spaced intervals along their length. For such a purpose Ihave shown in FIGURE 1 a plurality of spaced bores 64 in one pole piece36 adapted for alignment with other bores 64 formed in the other polepiece. When the two pole pieces 36 are brought together suitablefasteners can be inserted through the aligned bores 64 to securelymaintain the pair of pole pieces in assembled relationship.

In order to protect the pole pieces against deterioration from exposureto the water, and in the case of wooden pole pieces 36a, to preventattack by marine borers, it is preferable that the sheet 32 have a widthgreater than the circumference of the pile 50 as is indicated in FIG URE4. This excess width should be at least sufficient to wrap the pair ofpole pieces in edge portions of the sheet 32 one or two times when thepair of pole pieces are rotated to contract the encasement against thepile 5t). Thereafter, the pair of pole pieces are protected against thecorrosive efiect of the ambient water or against marine borer attack.

The wrapped pair of pole pieces 36 and edge portions of the sheet 32,have a substantial combined girth. As a result, a part of the sheet 32extends tangentially between the pile 59 and the wrapped pole pieces 36leaving gap 66 between the sheet 32 and pile 50 running the length ofpole pieces 36. As a result, some of the ambient water may circulatethrough the gap 66, thus hindering the maintenance of a stagnantcondition inside the encasement. In some ports or geographical locationsthis may not be critical, but in other localities where marine borerattack is severe and continuous it is desirable to close the gap 66, atleast at the lower end of the encasement 39.

A skirt 46, comprising a portion of sheet 32 depending beneath the polepieces 36, aids in closing the gap 66 at the lower end of the encasement30, and in protecting the extreme lower ends of the pole pieces 36against exposure to the sea water or marine borer attack. Since the polepieces 36 terminate short of the lower end of the sheet 32, the skirt 46can be completely circumferentially clamped against the pile 50 withoutobstruction by the pole pieces 36 so that formation of any gap in theskirt portion of the sheet 32 is avoided. It will be understood howeverthat the skirt 46, like the balance of the sheet 32, is in contact withthe pile 50 for the major portion of the circumference of the pile andis open only at gap 66. However a complete band around the skirt 46 canbe very readily applied and enhances the intimacy of the engagement ofthe skirt with the pile 5i} p and therefore the use of a completecircular band is preferred, rather than some less than circular meansadapted to fit only over the gap 66.

The skirt closing bands can be made of any suitable plastic material. Apreferred form of such band is indi cated in FIGURE 9 and indicated bythe numeral 68. This band 68 has a length approximately the same as thecircumference of pileStl. one end band 63 is formed with alongitudinally elongate eye 70 adapted for cooperative engagement by ahook 72 formed in the opposite end of band 68. Since band 68 ispreferably in a state of tension when applied to the skirt 46, the eye76 and hook 72 should be of such a configuration as to avoid rupture ofthe material of the band, particularly at the eye 70. This is importantfor insuring a long service life for the band 63.

To accomplish this, the eye 76 comprises a longitudinally elongate slit74 of a length approximately the same as the width of band 63 andterminating at both ends in arcuate openings '76 adapted to avoid theconcentration of rupturing stresses in the ends of eye 79 when hook 72is placed therein. The hook 72 is generally T-shaped in configurationand has a stem section 78 which is wider on the inside of band 68 thanon the outer surface of the band. The stem 78 is therefore wedge-shapedin cross section and narrows as it develops toward the adjacent end ofthe band 68. The head 80 of hook 72 is of the same width as the majorportion or the band 68 proper and has a junction with the stem portion78 in a pair of opposite shoulders 82, which are preferably CtIlgUi'ailyrelated and convergent towards the adjacent end of the band 68.

The band 68 can be installed either from the surface of the body ofwater 52 or by a diver. With the former procedure the hook 72 and eye74) are connected after band 63 has been placed around the pile 5 oraround the upper end of the encasement 3t Thereafter, even through theband 68 is under tension, it can he slid downwardly over the encasement31) until it snaps or contracts into place around skirt 46 after passingover the lower end of the pole pieces 36. This can be accomplished byusing a pair of long poles, notched at their lower ends to hold theband, inserted on opposite sides of the pole between the pile and band,to push the hand down. As is apparent, when the band 63 is to beinstalled by a diver it can be carried in open condition to the bottomof encasement 30 by the diver, who thereafter stretches it around theskirt 46 and then connects the hook 72 through the eye 70. In makingthis connection it is preferable to twist the head 89 of hook 72 90 fromits normal condition to pass it through the slit 74 of eye 70, which isof approximately the same width as the head 3t After engagement it willbe noted that the wedge-like contiguration of stem portion 78 of thehook 72 prevents a sharply divergent separation of the opposite sides ofthe slit 74 of eye 70 so that concentration of stresses is minimized.

It will be apparent that other fastening means can be utilized in lieuof the hook-and-eye means 70 and 72. For example, opposite ends of anelastic band can be vulcanized or cemented together, or stapled orriveted. However these alternate fastening means involve expenditures oftime and labor which are avoided by the band 68. Vulcanizing orcementing involve lapses of time merely in waiting for the joined partsto be securely connected and also require the use of specializedequipment. On the other hand the band 68 can be fabricated easily, evenin the field.

The upper end of the encasement 30 will normally be positioned above thehigh-tide line of the body of water 52 where it will usually be safefrom marine borer attack. If desired, the further precaution may betaken of closing the gap 66 at the upper end of the encasement 30 inorder to restrict circulation of the ambient Water therein. due to Waveaction. Where closure of the upper end of the encasement 30 is desired aband 84-, such as that shown in FIGURE 13, can be employed for thepurpose.

The band 84 is also preferably made of a rubber-like material andincludes an integral rigid U-shaped section 86 adapted forsemi-circularly embracing the pair of Wrapped pole pieces 36 at theupper end of the encasement 30. The U-shaped portion 86 may be definedby a complementarily shaped metal insert molded within the band 34 ormay be otherwise reinforced against separation of the opposite armsthereof when the band 8 5 is stretched. in use, the band 84 ispositioned at the upper end of the encasement 30' with the wrapped polepieces as received within the U-shaped portion 86, thus closing the gap60. Thereafter, the ends 84 can be vulcanized or cemented together.Alternatively the opposite ends of the band 04 can be formed withhook-and-eye means '70-72 as illustrated in FIGURE 11a.

In order to minimize the circulation of Water behind the encasement 30 Ihave utilized a pair of elastic boots 83, also preferably made from arubber-like material. Such boots can be used in addition to, or in lieuof the gap closing bands. Referring to FIGURE it will be seen that theboots 88 comprise relatively Wide elastic bands Whose opposite ends arevulcanized or cemented together after the band has been stretched andplaced in tension around the pile 50. This operation preferably takesplace on the pile above the upper end of encasement 30. Afterfabrication, one band 88 is expanded by any suitable means, such as aplurality of poles, and guided and slipped downwardly over the pile 50and encasement 30 to be positioned around the skirt 46, immediatelybeneath the lower ends of the pole pieces 36. Another band 88 is thenslipped down to the position indicated in FlGURE 11 to embrace both thepile 50 and the extreme upper end of the pole pieces 36 and sheet 32.

Another form of boot 90 is illustrated in FIGURE 11a. In this instancethe boot 90 comprises a relatively wide band of rubber-like materialwrapped in a position around the pile 50, the extreme upper end of polepieces 36, and the upper edge of sheet 32 and is held in place by nailsor other suitable fasteners 92. It will be observed that the nails $2are not driven through any part of the sheet 32 since itis desirable tomaintain the integrity of the sheet.

If desired, any of these boots which are to be used at the upper end ofan encasement can be made of a heavy material to also serve as fenders.The boots can also be relatively short encasements secured in place by afastener in their pole pieces and the pole pieces placed on top of thegap 66 of the main encasement to close the gap.

Depending upon local conditions, the area of the pile which is subjectto marine borer attack may extend from well above the tide line to themud line of the body of water. Although the encasement 30 has beenillustrated in the drawings as being finally installed with its lowerend terminating above the mud line 92 of the body of water 52, it istobe understood that, with or without the skirt portion 46, it canequally well be installed with its lower end positioned beneath the mudline 92. By the same token, the alternate form of encasement 100illustrated in FIGURES 14 through 21, while illustrated as being finallyinstalled with its lower end beneath the mud line 2, can equally well beinstalled in the position illustrated for the encasement 30.

The encasement 100 is particularly well adapted for application toextremely long piles 102 where the pile must be protected down to themud line 92 of the body of water 52. As with the encasement 30, it mayfrequently be necessary to make such installation within a limitedworking space as when a decking is supported On the piles 102 in closeproximity to the surface of the body of water 52. It is, of course,desirable to be able to make such an installation Without tearing up anydecking and it is also desirable to be able to make such an installationentirely from the surface of the body of water 52 without the aid of anyunderwater workers.

8 he encasement 100, like encasement 30, has particular utility insituations such as those just mentioned.

Encasement comprises a substantially rectangular sheet 10 of asubstantially Waterproof pliable material and a tubular pole piece 106.The sheet 104 is made of the same class of materials as sheet 32 and isof a length. sufiicient to reach from a point above the mean tide levelof the body of water 52 down to a point one or two feet below the mudline 92. This sheet 104 is also preferably tapered to conform to thepile taper and has a width throughout its length exceeding thecorresponding circumference of the pile 102, this excess widthpreferably being sufiicient to provide enough material to wrap the polepiece 106 within the pair of vertical edge portions of the sheet 104when the sheet is contracted into snug engagement with the pile 102.

Each of the opposite vertical edges of the sheet 104 is provided with anenlarged bead 103 that is preferably integrally formed andsemi-cylindrical in configuration, both of the heads 108 preferablybeing disposed on the same surface of the sheet 104. However, it will beapparent that the beads may assume other configurations and may also beseparately formed and afixed to opposite vertical edges of the sheet 104by vulcanizing, cementing, or suitable fasteners.

The pole piece res is preferably made of a metal, such as Monel, adaptedto successfully resist corrosion from sea water action but may also beof wood or plastic. As indicated in FIGURE 22, the pole piece 106 isthin walled, but should have sufiicient rigidity to support the sheet104 during installation and be capable of withstanding the forcesapplied to it during the twisting operation without undue distortion.Along one side, the pole piece 106 is formed with a longitudinallyextending slot 110, preferably running the entire length of the polepiece 106, and this slot should be wide enoughto easily accommodatetwice the thickness of the intermediate portions of the sheet 104, sothat a double thickness of sheet 104 can be readily slid through theslot 110. By the same token, the interior diameter of the tube 106should be large enough to easily slidably accommodate the pair of beads103. The combined thickness of the beads 108 is greater than the Widthof the slot 110 whereby th eedges of the sheet 104 are restrainedagainst movement radially outwardly of the pole piece 106.

In the installation of the encasement 100, the sheet 104 is rolled upabout a transverse axis on a spindle or other suitable support and heldin position adjacent the upper end of the pile 102. The pole piece 106is then placed in a vertical position adjacent the pile 102 with itslower end supported on the bottom or mud line 92. It will be observedthat the pole piece 106 is disposed on the side of pile 102 oppositefrom the rolled up sheet 104 and the slot 110 of pole piece 106confronts the pile 102. The pair of beaded edges 108 of the free end ofthe sheet 104 are then slid into the open upper end of the pole piece106 with a double thickness of the sheet 104 slidably entering the slot110. Thus, as the sheet 104 is slid downwardly over the pile 102 and asthe beaded edges 108 concurrently are moved downwardly through the polepiece 106, the sheet as it is unrolled assumes a tubular configurationsurrounding the pile 102.

This installation of sheet 104 around pile 102 can be accomplished, ifdesired, with the aid of a diver to pull the sheet 104 downwardly.However, in order to make an installation of encasement 100 entirelyfrom the surface of the body of Water 52, a pusher rod 112 can be used,such as is generally shown in FIGURE 17. The pusher rod 112 isconveniently made up of a number of telescopically connectable shorttubular sections 114. A lowermost section 116 is provided at its lowerend with a clamping means 118 for gripping the lower edges of the sheet104. The clamp means 118 is actuated by an elongate member (not shown)passing through the tubular sections 114 and 116 and connected to ahandle device 1 at the upper end of rod 112 for releasing the clampmeans 118 from engagement with the sheet 104. As many tubularintermediate sections 114 as desired can be employed for making up apusher rod 112 of the length necessary to push the sheet 164 downwardlyto the mud line 92 and through the pole piece 106.

To facilitate contraction of the sheet 104, the sheet should be pusheddownwardly to a position in which its upper edge is beneath the upperend of the pole piece 106 whereby a handle portion 122 of the pole pieceprojects above the upper edge of the sheet 104. At the same time, if itis desired to have a skirt portion 124 at the lower end of the sheet194, the sheet 104 should be pushed downwardly until its lower end isbeneath the lower end of the pole piece 106.

When the encasement 109 is in the position of FIG- URE 18, the pusherrod 112 is removed by actuation of the handle portion 122. Thereafter,the pole piece 106 is rotated, as indicated by the directional arrow 126in FIGURE 21, in order to take up the slack in the sheet 104, but notfully contracting the sheet into engagement with the pile 192. A lance128 is then directed to the junction of the pile 102 with the bottom 92and compressed air or water directed through the lance to create a smallcrater 13%, one or two feet in depth. Since the encasement llltl hasalready been preliminarily closed into contact with the pile 1&2, noneof the material removed from the crater 130 will enter thereinto. Insome instances, if the water is made turbid by the action of the lance128, it may be desirable to employ the services of a diver to ascertainthat the crater 130 is properly formed. Alternatively, the diver may, ofcourse, create the crater 130 with hand tools.

After removal of the lance 128, encasement 10b is lowered into its finalposition, indicated in FIGURE 20, with its lower end seated in thebottom of the crater 130. Pole piece W6 is then further twisted in thesame direction until the sheet 1d4 fits smoothly around the pile 102. Alag bolt 132 is then inserted through a bore 134 in the handle portion122 of the pole piece 106 and fastened into the pile 1&2 whereby thepole piece 106 is held against counter-rotation and the fit of theencasement 1% on the pile 162 is maintained. Tidal action of the body ofwater 52 will very shortly fill in the crater 13% so that the lower endof the encasement 104) is efl'ectively sealed against penetration bymarine borers or excessive circulation of water.

If desired, a suitable band or other clamping means may be alfixedaround the skirt portion 124, in the same manner as with the encasement30. Similarly, the upper end of encasement 1% can also be further closedby a clamping band. If desired, any water entrapped within the polepiece 106 can be evacuated by filling it with a material such as oil,mastic, or paint which will displace the trapped water and thus inhibitcorrosion of the pole piece 106. The pole piece 1th; may be protectedagainst corrosion by providing enough width in the sheet .104 tocompletely wrap the pole piece 106. The use of the single tubular polepiece 106 results in the creation of a gap similar to the gap 66 definedwith the use of encasement 30. However, if desired, this gap iselfectively sealed by the back filled crater 139. If the encasement 100is not installed with its lower end in the bottom 92, the gap can beclosed, if desired, by a clamping means around the skirt 124 or, if noskirt is provided, by a clamping band similar to either one of the boots8S and 90.

A number of important advantages arise out of the removable constructionof the encasements and 100. For example, in the event of rupture of thematerial of the sheet of these encasements, by floating debris or othermechanical action, the encasement can be quickly removed and readilyrepaired by a conventional patch. If it is desired to make periodicinspections of the piles, the encasements can be removed and replacedwith a minimum expenditure of time and effort to expose the pile to viewto ascertain whether or not any marine borer activity is going on. Thisremovable feature also permits vertical adjustment of the encasement tochange its position to meet a change in the area of the pile subjectedto marine borer attack. For example, if the mud line 92 should lower, asit will in some locations, to such an extent that it exposes the lowerend of the surrounding encasement, the encasement can be quickly removedand lowered into a new position in a new crater and once again fastenedinto place.

In the use of these encasements, they can be applied to new pilings inlieu of any of the conventional creosote or any other protection.Alternatively, a newly creosoted pile may be put in place and leftwithout the protection of my encasements until such time as asubstantial part of the creosote has leached from the pile. Theseencasements are then applied to the pile to arrest any marine boreractivity which has already ensued and to prevent any further marineborer attack. This greatly extends the service life of an initiallycreosoted pile which, without my invention, would very shortly becondemned as structurally unsound.

Although the species of the invention herein shown and described arefully capable of achieving the objects and providing the advantageshereinbefore mentioned, it is to be understood that they and the severaldetails of construction thereof are merely illustrative and that I donot mean to limit myself to the details of construction shown anddescribed other than as defined in the following claims.

I claim:

1. A method of protecting against marine borer attack a partiallysubmerged structure-bearing wooden pile, the upper end of which isobstructed, comprising: positioning a sheet of pliable substantiallywaterproof material alongside of a section of said pile to be protected,wrapping said sheet around said pile section to dispose oppositelongitudinal edges of said sheet in substantial juxtaposition extendinggenerally longitudinally of said pile, over lapping the oppositelongitudinal edges of said sheet, drawing said sheet about said pilesection to reduce the effective diameter enclosed by said sheet untilsaid sheet engages said pile throughout a substantial portion of thelength of said pile section, securing said sheet about said pile sectionin reduced diameter condition to define a generally circumferentialwater-filled space between said pile and said sheet, and retaining waterwithin said space with circulation between said space and the water surrounding said sheet being restricted to thereby maintain the water insaid space stagnant to prevent marine borer attack on the submergedportion of said pile encased by said sheet.

2. A method of protecting against marine borer at tack a partiallysubmerged structure-bearing wooden pile, the upper end of which isobstructed, with such piling ex tending upwardly from the mud line of abody of water, comprising: forming a crater lower than the mud lineadjacent said pile, positioning a sheet of pliable substantiallywater-proof material alongside of a section of said pile to beprotected, wrapping said sheet around said pile section to disposeopposite longitudinal edges of said sheet in substantial jutapositionextending generally longitudinally of said pile, overlapping theopposite longitudinal edges of said sheet, drawing said sheet about saidpile section to reduce the effective diameter enclosed by said sheetuntil said sheet engages said pile throughout a substantial portion ofthe length of said pile section, lowering said sheet until its lower endis disposed within said crater, securing said sheet about said pilesection in reduced diameter condition to define a generallycircumferential water-filled space between said pile and said sheet, andretaining water within said space with circulation between said spaceand the water surrounding said sheet being restricted to therebymaintain the water in said space stagnant to prevent marine borer attackon the submerged portion of said pile encased by said sheet.

3. A method of protecting against marine borer attack a partiallysubmerged structure-bearing wooden pile, the upper end of which isobstructed, comprising: positioning asheet of pliable substantiallywaterproof material alongside of a section of said pile to be protected,wrapping said sheet around said pile section to dispose oppositelongitudinal edges of said sheet in substantial juxtaposition extendinggenerally longitudinally of said pile, stififening said oppositelongitudinal edges, overlapping the opposite longitudinal edges of saidsheet, drawing said sheet about said pile section to reduce theeifective diameter enclosed by said sheet until said sheet engages saidpile throughout a substantial portion of the length of said pilesection, securing said sheet about said pile section in reduced diametercondition to define a generally circumferentially water-filled Spacebetween said pile and said sheet, and retaining Water within said spaceWith circulation between said space and the water surrounding said sheetbeing restricted to thereby maintain the water in said space stagnant toprevent marine borer attack on the submerged portion of said pileencased by saidsheet.

4. A method of protecting against marine borer attack a partiallysubmerged structure-bearing wooden pile, the upper end of which isobstructed, with such piling extending upwardly from the mud line of abody of Water, comprising: forming a crater lower than the mud lineadjacent said pile, positioning a sheet of pliable substantiallywaterproof material alongside of a section of said pile to be protected,wrapping said sheet around said pile section to dispose oppositelongitudinal edges of said sheet in substantial juxtaposition extendinggenerally longitudinally ofsaid pile, stiffening said oppositelongitudinal edges, overlapping the opposite longitudinal edges of saidsheet, drawing said sheet about said pile section to reduce theeffective diameter enclosed by said sheet until said sheet engages saidpile throughout a substantial portion of the length of said pilesection, lowering said sheet until its lower end is disposed withinsaid'erater, securing said sheet about said pile section in reduceddiameter condition to define a generally circumferential water-filledspace between said pile and said sheet, and retaining water within saidspace with circulation between said space and the water surrounding saidsheet being restricted to thereby maintain the water in said spacestagnant to prevent marine borer attack on the submerged portion of saidpile encased by said sheet.

References Eite-d in the file of this patent UNITED STATES PATENTS62,295 Smith Feb. 19, 1867 333,204 Dolbeer Dec. 29, 1885 395,866Anderson et al. Jan. 8, 1889 942,761 Voynow Dec. 7, 1909 1,244,119Mulnix et a1. Oct. 23, 1917 1,252,645 Baier Jan. 8, 1918 1,353,598 Lewisept. 21, 1920 1,546,860 Neubort July 21, 1925 1,963,436 Durnke June 19,1934 2,385,869 Lane Oct. 2, 1945 2,659,687 Moore Nov. 17, 1953 2,757,428Stark Aug. 7, 1956 2,853,758 Topf Sept. 30, 1958 FOREIGN PATENTS 669,489Germany Dec. 28, 1938 331,576 Italy Nov. 9, 1935 OTHER REFERENCES Smith:Preservation of Piling Against Marine Wood Borers, U.S. Dept. of Agr.,Forest Service, Circ. 128, 1908, 16 pp.; esp. pp. 8-11.

Atwood: Marine Piling Investigation, National Research Council,Washington, D.C., 1924, pp. 87-106.

